Cooking apparatus and control method thereof

ABSTRACT

A cooking apparatus comprises a body forming a cavity, a temperature sensor configured to detect a temperature of the cavity, a burner configured to heat the cavity by burning gaseous fuel, and a controller configured to identify a temperature variation of the cavity based on the temperature detected by the temperature sensor, and configured to stop an operation of the burner based on a change in the temperature variation of the cavity being less than a reference value.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application, under 35 U.S.C. §111(a), of International Patent Application No. PCT/KR2020/015763, filedon Nov. 11, 2020, which claims the benefit of Korean Patent ApplicationNo. 10-2020-0000118, filed on Jan. 2, 2020, and Korean PatentApplication No. 10-2020-0039293, filed Mar. 31, 2020, in the KoreanIntellectual Property Office, the entire disclosures of each of whichare incorporated herein by reference as a part of this application.

BACKGROUND Field

The present disclosure relates to a cooking apparatus and a controlmethod thereof, and to a technology capable of identifying incompletecombustion due to closure of an air outlet, by detecting an internaltemperature of a cavity of the cooking apparatus.

Description of Related Art

In general, a cooking apparatus is an appliance that cooks food byheating, and is roughly classified into a method of generating heat forheating food using electricity and a method of generating heat forheating food by burning gas.

The cooking apparatus is a kind of home appliance that cooks food byheating the food to a high temperature with a cavity in which food isaccommodated, a burner for generating heat by burning gas and air, a gassupply flow path for supplying gas to the burner, and an ignition devicefor generating a flame.

As is known, air is required for combustion and after combustion occurs,combustion gas corresponding to waste gas is generated. Therefore, thecooking apparatus further includes a supply flow path for supplying airto the cavity and an exhaust flow path for discharging the waste gas ofthe cavity. In addition, the cooking apparatus is provided with an airoutlet for discharging the waste gas.

When the air outlet of the cooking apparatus is closed due to the user'scarelessness, etc., the combustion gas corresponding to the waste gas isnot discharged to the outside of the cooking apparatus, and air forcombustion is not supplied, so the unburned gas is filled in the cavity.Recently, there is an increasing need to identify a situation, in whichthe air outlet of the cooking apparatus is closed, by detecting aninternal temperature of the cavity to secure stability of an operationof the cooking apparatus.

SUMMARY

One aspect of the present disclosure provides a cooking apparatusincluding a body forming a cavity, a temperature sensor configured todetect a temperature of the cavity, a burner configured to heat thecavity by burning gaseous fuel, and a controller configured to identifya temperature variation of the cavity based on the temperature detectedby the temperature sensor, and configured to stop an operation of theburner based on a change in the temperature variation of the cavitybeing less than a reference value.

The controller may be configured to identify the change in thetemperature variation of the cavity based on a change between atemperature variation of the cavity at a first time and a temperaturevariation of the cavity at a second time.

The controller may be configured to stop the operation of the burnerbased on the change in the temperature variation of the cavity beingless than the reference value during a first reference time.

The controller may be configured to continue the operation of the burnerbased on the change in the temperature variation of the cavity beinggreater than or equal to the reference value during a second referencetime.

An operation of the cooking apparatus may include a pre-heatingoperation for pre-heating the cavity and a cooking operation for cookingfood accommodated in the cavity. The controller may be configured tocontrol the cooking apparatus to start the cooking operation in responseto the temperature of the cavity detected by the temperature sensorbefore the pre-heating operation, being greater than or equal to areference temperature, and configured to control the cooking apparatusto start the pre-heating operation in response to the temperature of thecavity being less than the reference temperature.

The cooking apparatus may further include a convection fan. Thecontroller may be configured to drive the convection fan to circulateair inside the cavity based on the change in the temperature variationof the cavity being less than the reference value.

The cooking apparatus may further include a display. The controller maybe configured to cause the display to display a message indicating anoperation error of the cooking apparatus based on the change in thetemperature variation of the cavity being less than the reference value.

Another aspect of the present disclosure provides a control method of acooking apparatus including a body forming a cavity, and a burnerconfigured to heat the cavity by burning gaseous fuel, the controlmethod including driving the burner, detecting a temperature of thecavity, identifying a temperature variation of the cavity based on thedetected temperature, and stopping an operation of the burner based on achange in the temperature variation of the cavity being less than areference value.

The identifying of the change in the temperature variation of the cavitymay include identifying the change in the temperature variation of thecavity based on a change between a temperature variation of the cavityat a first time and a temperature variation of the cavity at a secondtime.

The stopping of the operation of the burner may include stopping theoperation of the burner based on the change in the temperature variationof the cavity being less than the reference value during a firstreference time.

The control method may further include continuing the operation of theburner based on the change in the temperature variation of the cavitybeing greater than or equal to the reference value during a secondreference time.

An operation of the cooking apparatus may include a pre-heatingoperation for pre-heating the cavity and a cooking operation for cookingfood accommodated in the cavity. The control method may further includestarting the cooking operation in response to the temperature of thecavity detected by the temperature sensor before the pre-heatingoperation, being greater than or equal to a first reference temperature,and starting the pre-heating operation in response to the temperature ofthe cavity being less than the reference temperature.

The control method may further include driving a convection fan tocirculate air inside the cavity based on the change in the temperaturevariation of the cavity being less than the reference value.

The control method may further include controlling a display to displaya message indicating an operation error of the cooking apparatus basedon the change in the temperature variation of the cavity being less thanthe reference value.

Another aspect of the present disclosure provides a cooking apparatusincluding a body forming a cavity, a temperature sensor configured todetect a temperature of the cavity, a burner configured to heat thecavity by burning gaseous fuel, and a controller configured to stop anoperation of the burner in response to the temperature of the cavitydetected by the temperature sensor after a predetermined time elapsessince an operation of the cooking apparatus starts, being less than apredetermined temperature.

The operation of the cooking apparatus may include a pre-heatingoperation for pre-heating the cavity and a cooking operation for cookingfood accommodated in the cavity. The controller may be configured tocontrol the cooking apparatus to start the cooking operation in responseto the temperature of the cavity detected by the temperature sensorbefore the pre-heating operation, being greater than or equal to apredetermined first reference temperature, and configured to control thecooking apparatus to start the pre-heating operation in response to thetemperature of the cavity being less than the predetermined firstreference temperature.

The controller may be configured to stop the operation of the burner inresponse to the temperature of the cavity detected by the temperaturesensor after a predetermined first reference time elapses since thepre-heating operation of the cooking apparatus starts, being less than apredetermined second reference temperature.

The controller may be configured to control the cooking apparatus tocontinue the cooking in response to the temperature of the cavitydetected by the temperature sensor after the predetermined secondreference time elapses since the cooking operation of the cookingapparatus starts, being greater than or equal to a predetermined thirdreference temperature.

The controller may be configured to stop the operation of the burner inresponse to the temperature of the cavity detected by the temperaturesensor after the predetermined second reference time elapses since thecooking operation of the cooking apparatus starts, being less than thepredetermined third reference temperature.

The cooking apparatus may further include a convection fan. Thecontroller may be configured to drive the convection fan to circulateair inside the cavity in response to the temperature of the cavitydetected by the temperature sensor after the predetermined time elapsessince the operation of the cooking apparatus starts, being less than thepredetermined temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating an exterior of a cooking apparatusaccording to one embodiment of the present disclosure.

FIG. 2 is a view illustrating an inside of the cooking apparatusaccording to one embodiment of the present disclosure.

FIG. 3 is a block diagram of the cooking apparatus according to oneembodiment of the present disclosure.

FIG. 4 is a view illustrating a state in which an air outlet of thecooking apparatus according to one embodiment of the present disclosureis closed.

FIG. 5 is a flowchart illustrating a control flow in pre-heating of thecooking apparatus according to one embodiment of the present disclosure.

FIG. 6 is a flowchart illustrating a control flow in cooking of thecooking apparatus according to one embodiment of the present disclosure.

FIGS. 7, 8 and 9 are graphs illustrating a temperature variation of acavity of the cooking apparatus according to one embodiment of thepresent disclosure.

FIG. 10 is a view illustrating a state of displaying a warning messagefor abnormal operation of the cooking apparatus according to oneembodiment of the present disclosure.

FIG. 11 is a view illustrating a state in which the warning message forabnormal operation of the cooking apparatus according to one embodimentof the present disclosure is displayed on a user terminal.

FIG. 12 is a flowchart illustrating a control flow in the cooking of thecooking apparatus according to one embodiment of the present disclosure.

FIG. 13 is a graph illustrating a temperature of the cavity of thecooking apparatus according to one embodiment of the present disclosure.

FIG. 14 is a graph illustrating a temperature variation of the cavity ofthe cooking apparatus according to one embodiment of the presentdisclosure.

FIG. 15 is a flowchart illustrating a control flow in the cooking of thecooking apparatus according to one embodiment of the present disclosure.

FIG. 16 is a graph illustrating a change in temperature variation of thecavity of the cooking apparatus according to one embodiment of thepresent disclosure.

DETAILED DESCRIPTION

In the following description, like reference numerals refer to likeelements throughout the specification. Well-known functions orconstructions are not described in detail since they would obscure theone or more exemplar embodiments with unnecessary detail. Terms such as“unit”, “module”, “member”, and “block” may be embodied as hardware orsoftware. According to embodiments, a plurality of “unit”, “module”,“member”, and “block” may be implemented as a single component or asingle “unit”, “module”, “member”, and “block” may include a pluralityof components.

It will be understood that when an element is referred to as being“connected” another element, it can be directly or indirectly connectedto the other element, wherein the indirect connection includes“connection via a wireless communication network”.

Also, when a part “includes” or “comprises” an element, unless there isa particular description contrary thereto, the part may further includeother elements, not excluding the other elements.

Throughout the description, when a member is “on” another member, thisincludes not only when the member is in contact with the other member,but also when there is another member between the two members.

It will be understood that, although the terms first, second, third,etc., may be used herein to describe various elements, but is should notbe limited by these terms. These terms are only used to distinguish oneelement from another element.

As used herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

An identification code is used for the convenience of the descriptionbut is not intended to illustrate the order of each step. The each stepmay be implemented in the order different from the illustrated orderunless the context clearly indicates otherwise.

The present disclosure is directed to providing a cooking apparatuscapable of improving stability of a product operation and securing usersafety by stopping an operation of the cooking apparatus by identifyinga situation, in which an air outlet is closed, through detection of aninternal temperature of a cavity of the cooking apparatus, and controlmethod thereof.

It is possible to obtain an effect of improving stability of a productoperation by stopping an operation of a cooking apparatus by identifyinga situation, in which an air outlet is closed, by detecting an internaltemperature of a cavity of the cooking apparatus. In addition, it ispossible to obtain an effect of securing the safety of the user from thedifficulty that the flame is discharged out of an oven due to sudden gascombustion caused by opening of the cavity filled with the unburned gas.

Reference will now be made in detail to embodiments of the disclosure,examples of which are illustrated in the accompanying drawings.

FIG. 1 is a view illustrating an exterior of a cooking apparatusaccording to one embodiment of the present disclosure, FIG. 2 is a viewillustrating an inside of the cooking apparatus according to oneembodiment of the present disclosure, FIG. 3 is a block diagram of thecooking apparatus according to one embodiment of the present disclosure,and FIG. 4 is a view illustrating a state in which an air outlet of thecooking apparatus according to one embodiment of the present disclosureis closed.

Referring to FIG. 1, a cooking apparatus 1 according to one embodimentof the present disclosure may include an oven 2 body in which variouscomponents are placed, and a cook top 10 configured to heat a cookingcontainer including food. The cooktop 10 may be positioned at an upperportion of the cooking apparatus 1, and the oven 2 may be positioned ata lower portion of the cooking apparatus 1. A cavity (not shown) may beformed in the oven 2. Food may be accommodated in the cavity.

In FIG. 1, the cooking apparatus 1 is illustrated as including thecooktop 10 and the oven 2, but, alternatively, the cooking apparatus 1may include only the oven 2. That is, in the cooking apparatus 1, thecooktop 10 may be omitted. The cooking apparatus 1 may be provided as abuilt-in or non-built-in type.

The cooktop 10 may include a gas burner device 100 for heating food. Thegas burner device 100 may use gas as an energy source. The gas burnerdevice 100 may generate thermal power by burning gas. In FIG. 1, thecooktop 10 is illustrated as including five gas burner devices 100, butthe number of gas burner devices 100 is not limited thereto.

The cooktop 10 may include a support plate 11. The support plate 11 mayform an upper surface of the cooking apparatus 1. The gas burner device100 may be mounted on the support plate 11.

A container support member 12 may be arranged on the upper portion ofthe support plate 11. The container support member 12 may be provided toplace a cooking container (not shown) thereon. The container supportmember 12 may be removable from the support plate 11. The containersupport member 12 may be located above the gas burner device 100. Thecontainer support member 12 may be provided in plurality.

The oven 2 may be provided under the cooktop 10. A plurality of racks(not shown) may be provided inside the oven 2, and a tray (not shown)may be mounted on each rack. Food to be cooked may be accommodated inthe tray.

The oven 2 may include a door 2 a configured to selectively open orclose the front side of the cavity 40. The door 2 a may include asee-through member 2 b formed of a transparent or semi-transparentmaterial to allow a user to visually check a cooking state of the foodaccommodated in the cavity 40. The see-through member 2 b may beprovided with multiple glass layers. The multiple glass layers may bespaced apart to allow air for cooling to pass therethrough.

A knob 3 may be provided on a front upper portion of the cookingapparatus 1. The knob 3 may be provided for setting functions of thecooktop 10 and/or the oven 2. The knob 3 may be provided to operate eachgas burner device 100. By operating the knob 3, the user can set on/off,a temperature, a time, and the like. Although it is illustrated thatfive knobs 3 are provided in FIG. 1, the present disclosure is notlimited thereto, and the number of knobs 3 may vary. The number of knobs3 may be provided to correspond to the number of gas burner devices 100.Each knob 3 may control each gas burner device 100 independently of eachother.

In addition, a user interface 5 may be provided next to the knob 3 onthe front upper portion of the cooking apparatus 1, and the userinterface 5 may include a plurality of input buttons 5 a configured toreceive control commands from the user, and a display 5 b provided todisplay operation information of the cooking apparatus 1.

When looking at the outside and inside of the cooking apparatus 1 inmore detail, the cavity 40 accommodating the food is formed inside abody 1 a. The cavity 40 is formed in a substantially box shape by anupper wall 31, a lower wall 32, a left wall 33, a right wall 34 and arear wall 35, and a front side of the cavity 40 is open for putting inand out of food.

A door 20 coupled to the body 1 a to be rotatable in the verticaldirection may be provided on the open front surface of the cavity 40,and the cavity 40 may be opened and closed by the door 20. In addition,the door 20 may be provided with a handle 2 c to allow a user to easilyopen and close the door 20.

In addition, a plurality of supports 36 on which the rack (not shown),on which food is placed, is mounted may be provided inside the cavity40. The plurality of supports 36 may protrude from the left wall 33 andthe right wall 34.

The cavity 40 may be partitioned by a divider 43. The divider 43 may beremovably mounted inside the cavity 40, and may divide the cavity 40,vertically or horizontally. For example, as shown in FIG. 2, the divider43 may be mounted parallel to the upper wall 31 and the lower wall 32 ofthe cavity 40 and thus the divider 43 may divide the cavity 40 to afirst cavity 41 in the upper portion and a second cavity 42 in the lowerportion.

The divider 43 may be formed of an insulating material, and the firstcavity 41 and the second cavity 42 may be insulated by the divider 43.In addition, it is not required that the first cavity 41 and the secondcavity 42 divided by the divider 43 have the same size, and thus thefirst cavity 41 and the second cavity 42 may have the different size.

In order to heat the food accommodated in the cavity 40, the cookingapparatus 1 may include various components.

Referring to FIGS. 1 to 3, according to one embodiment, the cookingapparatus 1 may include a plurality of burners 61 and 62 configured toheat the cavity 40 by burning gas fuel, a plurality of convection units51 and 52 configured to circulate air in the cavity 40, an auxiliary airsupply device 105 configured to assist in supplying air to the cavity40, the user interface 5 configured to interact with a user, and aplurality of temperature sensors 80: 81 and 82 configured to detect atemperature of the cavity 40.

The plurality of burners 60: 61 and 62 may include a first burner 61provided in an upper portion of the cavity 40 and a second burner 62provided in a lower portion of the cavity 40. Particularly, when thecavity 40 is divided into the first cavity 41 on the upper side and thesecond cavity 42 on the lower side by the divider 43, the first burner61 may be installed in the first cavity 41 and the second burner 62 maybe installed in the second cavity 42.

The first burner 61 may include a first pipe burner 61 b configured togenerate a flame for heating the food accommodated in the cavity 40, anda first burner valve 61 a configured to regulate gas fuel supplied tothe first pipe burner 61 b.

The first pipe burner 61 b may extend forwardly from a rear surface ofthe cavity 40, and a plurality of gas outlet holes through which gasfuel is discharged to generate a flame may be provided on a side surfaceof the first pipe burner 61 b.

The first burner valve 61 a may be arranged on a first gas supply pipe(not shown) supplying gas fuel from an external gas supply source (notshown) to the first pipe burner 61 b, so as to open and close the firstgas supply pipe. The first burner valve 61 a may employ a bimetal valve,and a solenoid valve.

Based on the cavity 40 being divided into the first cavity 41 and thesecond cavity 42 by the divider 43, the first burner 61 may heat thefood accommodated in the first cavity 41.

In addition, the first burner 61 may be provided to be exposed on theupper portion of the cavity 40. As a result, the first burner 61 maydirectly heat the food accommodated in the cavity 40 as shown in FIG. 2.Particularly, the food may be directly heated by radiant heat generatedby the flame of the first burner 61.

The second burner 62 may include a second pipe burner 62 b configured togenerate a flame for heating the cavity 40, and a second burner valve 62a configured to regulate gas fuel supplied to the second pipe burner 62b.

The second pipe burner 62 b may extend forwardly from the rear surfaceof the cavity 40, and a plurality of gas outlet holes through which gasfuel is discharged to generate a flame may be provided on a side surfaceof the second pipe burner 62 b.

The second burner valve 62 a may be arranged on a second gas supply pipe(not shown) supplying gas fuel from an external gas supply source (notshown) to the second pipe burner 62 b, so as to open and close thesecond gas supply pipe. The second burner valve 62 a may employ abimetal valve, and a solenoid valve.

Based on the cavity 40 being divided into the first cavity 41 and thesecond cavity 42 by the divider 43, the second burner 62 may heat thefood accommodated in the second cavity 42.

In addition, the second burner 62 may be provided under the lower wall32 of the cavity 40. As a result, the second burner 62 may indirectlyheat the food accommodated in the cavity 40 as shown in FIG. 2.Particularly, the air heated by the second burner 62 may be suppliedinto the cavity 40 through a heating hole 32 a of the lower wall 32, andthe food may be cooked by the heated air inside the cavity 40.

The plurality of convection units 51 and 52 are provided on the rearsurface of the cavity 40, and includes a first convection unit 51provided on an upper portion of the rear surface and a second convectionunit 52 provided on a lower portion of the rear surface. Particularly,based on the cavity 40 being divided into the first cavity 41 in theupper portion and the lower second cavity 42 in the lower portion by thedivider 43, the first convection unit 51 may be positioned in the firstcavity 41 and the second convection unit 52 may be positioned in thesecond cavity 42.

The first convection unit 51 may include a first convection fan 51 bconfigured to circulate air inside the cavity 40, a first auxiliaryheater 51 a configured to auxiliary heat the inside of the cavity 40,and a first convection housing 51 c provided to accommodate the firstconvection fan 51 b and the first auxiliary heater 51 a.

The first convection fan 51 b rotates by receiving a rotational forcefrom a first convection fan motor, and circulates air inside the cavity40. Particularly, the first convection fan 51 b provided on the rearsurface of the cavity 40 discharges air toward the front of the cavity40. The air discharged toward the front of the cavity 40 by the firstconvection fan 51 b circulates inside the cavity 40 and then returns tothe first convection fan 51 b.

Because the air inside the cavity 40 is circulated by the firstconvection fan 51 b, the inside of the cavity 40 may have a uniformtemperature distribution.

The first auxiliary heater 51 a heats the air discharged by the firstconvection fan 51 b. Particularly, the air heated by the first auxiliaryheater 51 a is discharged into the cavity 40 by the first convection fan51 b.

The first auxiliary heater 51 a radiates less heat than the first burner61 and the second burner 62. Accordingly, the first auxiliary heater 51a may be used to assist the first burner 61 and the second burner 62.

The second convection unit 52 may include a second convection fan 52 bconfigured to circulate air inside the cavity 40, a second auxiliaryheater 52 a configured to auxiliary heat the inside of the cavity 40,and a second convection housing 52 c provided to accommodate the secondconvection fan 52 b and the second auxiliary heater 52 a.

The second convection fan 52 b rotates by receiving a rotational forcefrom a second convection fan motor, and circulates the air inside thecavity 40. The second auxiliary heater 52 a heats air discharged by thesecond convection fan 52 b. The second auxiliary heater 52 a may radiateless heat than the first burner 61 and the second burner 62, and thesecond auxiliary heater 52 a may be used to assist the first burner 61and the second burner 62.

An air inlet (not shown) supplying air for combustion of the secondburner 62 is provided on the lower wall 32.

The auxiliary air supply device 105 may supply air for combustion of thefirst burner 61.

As is well known, air containing oxygen is required to burn fuel. If aircontaining oxygen is not supplied, the flame that burns the fuel isimmediately extinguished.

As described above, the first burner 61 and the second burner 62 heatthe cavity 40 by burning gas fuel. Also, as is widely known, because theburned gas moves from the bottom to the top, it is common to place theair inlet for supplying air in the lower portion of the cavity 40.Accordingly, the second burner 62 may receive fresh air from the airinlet (not shown) formed in the lower portion of the cavity 40. That is,a separate air supply device for supplying air to the second burner 62is not required.

On the other hand, because it is difficult for the first burner 61 toreceive air from the air inlet (not shown) formed in the lower portionof the cavity 40, a separate air supply for supplying fresh air to thefirst burner 61 is required. Moreover, when the cavity 40 is dividedinto the first cavity 41 and the second cavity 42 by the divider 43, thefirst cavity 41 is not provided with an air inlet, and thus an airsupply device for supplying fresh air to the first burner 61 isrequired.

In addition, in a state in which the divider 43 is not mounted, thecombustion waste gas generated by the second burner 62 provided in thelower portion of the cavity 40 interferes with the combustion of thefirst burner 61, and thus an air supply device for supplying fresh airto the first burner 61 is required. The waste gas refers to combustiongas generated after combustion. When the gas is completely combusted,carbon monoxide and water vapor are generated, and when the gas isincompletely combusted, carbon monoxide, hydrogen, sulfur, etc. may begenerated. Incomplete combustion may occur in the first burner 61 by thewaste gas of the second burner 62.

Therefore, the auxiliary air supply device 105 may be provided on theupper portion of the rear surface 35 of the cavity 40 so as to supplyfresh air to the first burner 61.

As shown in FIG. 1, an air outlet 90 extending to the outside of thecooking apparatus 1 so as to guide the waste gas of the cavity 40 to theoutside of the cooking apparatus 1 may be formed on the upper wall 31.In addition, based on the divider 43 being mounted to the cavity 40, theair outlet 90 may discharge the waste gas of the first cavity 41.

In addition, an auxiliary air outlet 91 provided to guide the waste gasof the second cavity 42 to the outside of the cooking apparatus 1 may beprovided on the rear wall 35. By the divider 43 being mounted to thecavity 40, it is difficult for the waste gas generated by the combustionof the second burner 62 to be discharged to the air outlet 90 of theupper wall 31. For this reason, the auxiliary air outlet 91 provided todischarge the waste gas of the second cavity 42 is provided at aposition corresponding to the second cavity 42.

The user interface 5 may be provided next to the knob 3 on the upperfront portion of the cooking apparatus 1, and include the plurality ofinput buttons 5 a receiving control commands from the user and thedisplay 5 b displaying operation information of the cooking apparatus 1.

The input button 5 a may receive a setting value related to theoperation of the cooking apparatus 1 or various control commands fromthe user.

For example, the user can set a cooking time, change a cookingtemperature, select the cavity (e.g., the first cavity or the secondcavity), or select a cooking method (e.g., baking cooking or boilingcooking) through the input button 5 a. In other words, the input button5 a may include a broil button (not shown) for inputting a broil cookingcommand of the first cavity 41, a bake button (not shown) for inputtinga bake cooking command of the first cavity 41, and a bake button (notshown) for inputting a bake heating command of the second cavity 42.

In addition, through the input button 5 a, the user may input apreheat-set temperature for pre-heating for the cooking apparatus 1 topreheat the cavity 40, and a cooking set temperature for cooking foodaccommodated in the cavity 40.

The input button 5 a transmits an electrical signal corresponding to theset value or control command input by the user to a controller 200.

The input button 5 a may employ a push switch, a toggle switch, asliding switch, a membrane switch, a touch switch, or a dial.

The display 5 b may display various operation information related to theoperation of the cooking apparatus 1 to the user in response to thecontrol signal of the controller 200. For example, the display 5 b maydisplay a cooking temperature or a cooking method selected by a user, ordisplay a current temperature of the cavity 40. Further, as will bedescribed later, the display 5 b may display a warning message regardingabnormal operation of the cooking apparatus 1.

The display 5 b may employ a light emitting diode (LED) panel, anorganic light emitting diode (OLED) panel, or a liquid crystal display(LCD) panel.

In addition, the display 5 b may employ a touch screen including a touchpad sensing a user's touch. The touch screen may display a setting valueor a control command that a user can select, and may receive a settingvalue or a control command in response to a user's touch input.

The temperature sensor 80 may include a first temperature sensor 81provided in the upper portion of the cavity 40 and a second temperaturesensor 82 provided in the lower portion of the cavity 40. Particularly,in the state in which the cavity 40 is divided into the upper firstcavity 41 and the lower second cavity 42 by the divider 43, the firsttemperature sensor 81 may detect a temperature of the first cavity 41and the second temperature sensor 82 may detect a temperature of thesecond cavity 42.

The first temperature sensor 81 and the second temperature sensor 82 mayinclude a thermistor in which electrical resistance changes according toa temperature. The first temperature sensor 81 and the secondtemperature sensor 82 including the thermistor may output an electricalsignal corresponding to the temperature of the cavity 40.

For example, in the state in which the divider 43 is mounted, the firsttemperature sensor 81 may output a first temperature detection signalcorresponding to the temperature of the first cavity 41 to thecontroller 200, and the second temperature sensor 82 may output a secondtemperature detection signal corresponding to the temperature of thesecond cavity 42 to the controller 200. In addition, in the state inwhich the divider 43 is separated, the first temperature sensor 81 andthe second temperature sensor 82 may output a first temperaturedetection signal and a second temperature detection signal correspondingto the temperature of the cavity 40 to the controller 200.

In addition, the cooking apparatus 1 according to one embodiment mayinclude the controller 200 configured to manage the control related tothe operation of the cooking apparatus 1, a communication circuitry 300configured to transmit data related to the operation of the cookingapparatus 1 to an external device, and configured to performcommunication between the cooking apparatus 1 and an external device, anotification device 400 configured to output a warning sound about theabnormal operation of the cooking apparatus 1, and a memory 220configured to store a program and data for controlling the cookingapparatus 1.

The controller 200 includes the memory 220 configured to store/memorizeprograms and data, and a processor 210 configured to process dataaccording to the programs and data stored in the memory 220.

The processor 210 processes a control command, first and secondtemperature detection signals according to the control program stored inthe memory 220, and output a control signal for controlling the firstburner 61, the second burner 62, the first convection unit 51, thesecond convection unit 52, and the auxiliary air supply device 105.

For example, in response to a broil cooking command for the first cavity41 being input from a user, the processor 210 may process the user'scontrol command and output a control signal for controlling the firstburner 61, the first convection unit 51 and the auxiliary air supplydevice 105 according to the first temperature detection signal.Particularly, in response to a temperature of the first cavity 41 beingless than the cooking temperature, the processor 210 may output acontrol signal for operating the first burner 61, the first convectionunit 51 and the auxiliary air supply device 105. In response to atemperature of the first cavity 41 being greater than or equal to thecooking temperature, the processor 210 may output a control signal forstopping the first burner 61, the first convection unit 51 and theauxiliary air supply device 105.

The memory 220 may store the control program and control data forcontrolling the cooking apparatus 1, the control command input through auser interface, the first temperature detection signal and the secondtemperature detection signal input from the first temperature sensor 81and the second temperature sensor 82, and the control signal output fromthe processor 210.

In addition, the memory 220 may include a volatile memory (not shown)such as Static Random Access Memory (S-RAM), Dynamic Random AccessMemory (D-RAM), and a non-volatile memory (not shown) such as flashmemory, Read Only Memory (ROM), an Erasable Programmable Read OnlyMemory (EPROM), and an Electronically Erasable Programmable Read OnlyMemory (EEPROM).

The non-volatile memory may operate as an auxiliary storage device ofthe volatile memory, and may store the control program and control datafor controlling the operation of the cooking apparatus 1. In addition,the non-volatile memory may maintain the stored data even when the powerof the cooking apparatus 1 is turned off.

The volatile memory may load the control program and control data fromthe non-volatile memory and temporarily memorize the control program andcontrol data or may temporarily memorize the control command inputthrough the user interface, the first temperature detection signal andthe second temperature detection signal input from the first temperaturesensor 81 and the second temperature sensor 82, the control signaloutput from the processor 210, and operation information of the firstburner 61 and the second burner 62. Unlike the nonvolatile memory, thevolatile memory may lose the memorized data caused by the power off ofthe cooking apparatus 1.

In the above, the processor 210 and the memory 220 are described as aseparate component, but the present disclosure is not limited thereto,and the processor 210 and the memory 220 may be provided as a singlechip.

As mentioned above, the controller 200 may control operations of variouscomponents included in the cooking apparatus 1. Further, it may beunderstood that the operation of the cooking apparatus 1 to be describedbelow is performed by a control operation of the controller 200.

As described above in FIG. 1, the air outlet 90 is provided on the upperwall 31 of the cooking apparatus 1, and the air outlet 90 is formed toextend to the outside of the cooking apparatus 1 to discharge the wastegas of the cavity 40 to the outside of the cooking apparatus 1.

As shown in FIG. 4, due to the closure of the 90 caused by negligence ormistake, such as a state in which a user places an object ob on the airoutlet 90 during operation of the cooking apparatus 1, the waste gasburned inside the cooking apparatus 1 may stay inside the cavity 40without being discharged to the outside through the air outlet 90.

Due to the waste gas filled in the cavity 40, air for combustion may notbe supplied to the inside of the cooking apparatus 1, but gas may besupplied. Therefore, unburned gas is filled in the cooking apparatus 1.

When the user opens the door 2 a while the inside of the cookingapparatus 1 is filled with the unburned gas, air may flow into thecooking apparatus 1 and the unburned gas may be combusted to generate aflame, which may cause safety problems in that a user is burned.

FIG. 4 illustrates that the entire air outlet 90 of the cookingapparatus 1 is closed, as an example, but if the waste gas is notsmoothly discharged to the outside of the cooking apparatus 1 even whena part of the air outlet 90 is closed, the unburned gas is filled in thecooking apparatus 1.

According to the cooking apparatus and the control method thereofaccording to one embodiment of the present disclosure, in the state inwhich unburned gas is generated and filed in the cooking apparatus 1 dueto the closure of the air outlet 90 of the cooking apparatus 1, it ispossible to identify the state, in which the air outlet 90 is closed, bydetecting the internal temperature of the cavity 40 and to stop theoperation of the cooking apparatus 1.

FIG. 5 is a flowchart illustrating a control flow in pre-heating of thecooking apparatus according to one embodiment of the present disclosure,and FIG. 6 is a flowchart illustrating a control flow in cooking of thecooking apparatus according to one embodiment of the present disclosure.FIGS. 7 to 9 are graphs illustrating a temperature variation of a cavityof the cooking apparatus according to one embodiment of the presentdisclosure. FIG. 10 is a view illustrating a state of displaying awarning message for abnormal operation of the cooking apparatusaccording to one embodiment of the present disclosure, and FIG. 11 is aview illustrating a state in which the warning message for abnormaloperation of the cooking apparatus according to one embodiment of thepresent disclosure is displayed on a user terminal.

Referring to FIGS. 5 to 11, in response to the start of the operation ofthe cooking apparatus 1, the temperature sensor 80 may detect thetemperature of the cavity 40 (1000).

As described above, the first temperature sensor 81 may output the firsttemperature detection signal corresponding to the temperature of thefirst cavity 41 to the controller 200, and the second temperature sensor82 may output the second temperature detection signal corresponding tothe temperature of the second cavity 42 to the controller 200. Inaddition, in the state in which the divider 43 is separated, the firsttemperature sensor 81 and the second temperature sensor 82 may outputthe first temperature detection signal and the second temperaturedetection signal corresponding to the temperature of the cavity 40 tothe controller 200.

The operation and control method of the cooking apparatus 1 describedbelow may be equally applied to the first cavity 41 and the secondcavity 42, respectively, based on the divider 43 being mounted. That is,in the state in which the divider 43 is mounted, the controller 200 maydetermine the generation of unburned gas caused by the closure of theair outlet 90, based on the temperature of the first cavity 41 detectedby the first temperature sensor 81 and the temperature of the secondcavity 42 detected by the second temperature sensor 82, and may stop theoperation of the cooking apparatus 1.

On the other hand, in the state in which the divider 43 is separated,the controller 200 may determine the generation of unburned gas causedby the closure of the air outlet 90 based on the temperature of thecavity 40 detected by the first temperature sensor 81 and the secondtemperature sensor 82, and may stop the operation of the cookingapparatus 1.

The controller 200 may determine whether the temperature of the cavity40 detected by the temperature sensor 80 is greater than or equal to afirst reference temperature (1010). In this case, the first referencetemperature may be a set temperature input by a user through the inputbutton 5 a in advance, or may be temperature data stored in advance inthe memory 220.

The cooking apparatus 1 may be already in an operation state, orcomplete pre-heating, or complete cooking food prior to performing thecontrol method of the cooking apparatus 1 according to one embodiment.That is, in response to a currently-detected temperature of the cavity40 of the cooking apparatus 1 being greater than or equal to apredetermined temperature value, the controller 200 may determine thatthe pre-heating of the cooking apparatus 1 is already performed or thecooking food is already performed. Accordingly, the controller 200 maydetermine that the cooking apparatus 1 operates normally.

In response to the completion of the pre-heating of the cookingapparatus 1, the notification device 400 may output a notificationindicating that cooking may start. That is, in response to thecurrently-detected temperature of the cavity 40 of the cooking apparatus1 being greater than or equal to the first reference temperature, thenotification device 400 may output a notification indicating thecompletion of the pre-heating. Accordingly, a user may listen to thenotification sound and input a control command for starting the cookingof the cooking apparatus 1.

In response to the temperature of the cavity 40 being greater than orequal to the first reference temperature, the controller 200 may controlthe cooking apparatus 1 to start heating for the cooking (1060), and inresponse to the temperature of the cavity 40 being less than the firstreference temperature, the controller 200 may control the cookingapparatus 1 to start heating for the pre-heating (1020).

That is, as shown in FIG. 7, in response to the temperature of thecavity 40 being less than the first reference temperature, thecontroller 200 may control the cooking apparatus 1 to start thepre-heating before the cooking apparatus 1 starts the cooking, so as toheat the cavity 40 to a predetermined temperature during a firstreference time t1.

The controller 200 may determine whether the first reference time t1elapses since the start of the heating for the pre-heating of thecooking apparatus 1 (1030), and the temperature sensor 80 may detect thetemperature of the cavity 40 at the expiration of the first referencetime t1 (1040).

The controller 200 may determine whether the temperature of the cavity40 detected by the temperature sensor 80 is greater than or equal to asecond reference temperature (1050). In this case, the second referencetemperature may be a set temperature input by a user through the inputbutton 5 a in advance, or may be temperature data stored in advance inthe memory 220.

That is, the controller 200 may determine whether the temperature of thecavity 40 is greater than or equal to the predetermined temperatureduring a predetermined time, by the pre-heating of the cooking apparatus1, and in general, the temperature of the cavity 40 rises to the secondreference temperature or more during the first reference time t1, asillustrated in FIG. 7.

In response to the temperature of the cavity 40 being greater than orequal to the second reference temperature, the controller 200 maydetermine that the difficulty does not occur in the combustion processof the cooking apparatus 1, and the controller 200 may control thecooking apparatus 1 to start the heating for cooking (1060). Asdescribed above, in response to the completion of the pre-heating of thecooking apparatus 1, the notification device 400 may output thenotification indicating that cooking may start. That is, in response tothe currently-detected temperature of the cavity 40 of the cookingapparatus 1 being greater than or equal to the second referencetemperature, the notification device 400 may output the notificationindicating the completion of the pre-heating. Accordingly, a user maylisten to the notification sound and input a control command forstarting the cooking of the cooking apparatus 1.

However, as described above in FIG. 4, due to the closure of the airoutlet 90 such as the state, in which a user places an object ob on theair outlet 90, the waste gas burned inside the cooking apparatus 1 maystay inside the cavity 40 without being discharged to the outsidethrough the air outlet 90. Therefore, air for combustion may not besupplied to the inside of the cooking apparatus 1, which causes thegeneration of the unburned gas.

That is, gas is not completely burned inside the cooking apparatus 1,and thus the temperature of the cavity 40 does not rise. Accordingly, asillustrated in FIG. 8, a temperature of the cavity 40 detected by thetemperature sensor 80 is less than the second reference temperatureafter the first reference time t1 elapses since the start of thepre-heating of the cooking apparatus 1.

That is, in response to the abnormal performance of the pre-heating ofthe cavity 40, the notification device 400 may not output thenotification indicating the completion of the pre-heating, and output awarning sound indicating that a difficulty occurs in the combustionprocess of the cooking apparatus 1.

In response to the temperature of the cavity 40 being less than thesecond reference temperature after the pre-heating for the firstreference time t1, the controller 200 may determine that the difficultyoccurs in the combustion process of the cooking apparatus 1, such as thegeneration of the unburned gas caused by the closure of the air outlet90, and the controller 200 may stop the operation of the cookingapparatus 1.

Particularly, the controller 200 may control the operation of the burner60 to be stopped (1051). That is, by controlling the first burner valve61 a and the second burner valve 62 a included in the first burner 61and the second burner 62, respectively, the controller 200 may stop thegas supply so as to prevent the unburned gas from being filled in thecooking apparatus 1.

Further, the controller 200 may control the convection fan 50 b torotate for a predetermined first circulation time (1052). That is, bycontrolling each of the first convection fan 51 b and the secondconvection fan 52 b to rotate for the predetermined time, the controller200 may circulate the air inside the cavity 40 and allow the unburnedgas inside the cavity 40 to be discharged to the outside of the cookingapparatus 1.

The controller 200 may control the first convection fan 51 b and thesecond convection fan 52 b to rotate for the predetermined time, such as5 to 20 seconds, and thus the controller 200 may circulate the air inthe cavity 40 and discharge the unburned gas.

Further, the controller 200 may control the door 2 a of the cookingapparatus 1 to be locked for a predetermined first locking time (1053).That is, as described above, when a user opens the door 2 a in a statein which the unburned gas is filled in the cooking apparatus 1, air mayflow into the cooking apparatus 1 and the unburned gas may be burned,thereby discharging a flame to the outside of the cooking apparatus 1.Therefore, the controller 200 may control the door 2 a of the cookingapparatus 1 to be locked for the predetermined time until the unburnedgas of the cooking apparatus 1 is discharged to the outside ordisappears, and thus the controller 200 may secure the user's safety.

In addition, the controller 200 may control the notification device 400to transmit a warning sound indicating that the difficulty occurs in thecombustion process of the cooking apparatus 1, such as the generation ofthe unburned gas due to the closure of the air outlet 90 (1054).

The notification device 400 may be implemented in the form of a speakerthat outputs a voice signal or a sound signal, and may output a warningmessage regarding abnormal operation of the cooking apparatus 1 as apredetermined sound signal such as a voice or a warning sound. Thenotification device 400 may output the warning message once or mayoutput the warning message several times according to a predeterminedsetting.

Similarly, the controller 200 may control the display 5 b to display thewarning message indicating that the difficulty occurs in the combustionprocess of the cooking apparatus 1, such as the generation of theunburned gas due to the closure of the air outlet 90 (1054).

That is, as shown in FIG. 10, the controller 200 may display the messageregarding the abnormal operation of the cooking apparatus 1 on thedisplay 5 b, and a user may identify that the operation of the cookingapparatus 1 is stopped due to the generation of the unburned gas causedby the closure of the air outlet 90.

In addition, the controller 200 may control the communication circuitry300 to transmit at least one data of the warning sound or the warningmessage indicating that the difficulty occurs in the combustion processof the cooking apparatus 1, such as the generation of the unburned gasdue to the closure of the air outlet 90, to a user terminal 600 (1055).

The communication circuitry 300 may communicate with the user terminal600 configured to communicate with the cooking apparatus 1. The userterminal 600 may include a device configured to communicate with thecooking apparatus 1, such as a smart phone, a tablet PC, and a devicededicated to the cooking apparatus 1 provided for the purpose ofcontrolling the cooking apparatus 1.

The communication circuitry 300 may be implemented using a communicationchip, an antenna, and related components so as to access at least one ofa wired communication network and a wireless communication network. Thatis, the communication circuitry 300 may be implemented with varioustypes of communication modules configured to perform short-distancecommunication or long-distance communication with the user terminal 600.

Based on the data received from the cooking apparatus 1 through thecommunication circuitry 300, the user terminal 600 may output apredetermined sound signal, such as a voice or a warning sound,regarding an occurrence of the difficulty in the combustion process ofthe cooking apparatus 1, such as the generation of the unburned gas dueto the closure of the air outlet 90.

Further, as shown in FIG. 11, the user terminal 600 may display thewarning message indicating that the difficulty occurs in the combustionprocess of the cooking apparatus 1.

The user listens to the warning sound output from the user terminal 600,or checks the warning message displayed on the user terminal 600,thereby identifying that the operation of the cooking apparatus 1 isstopped due to the generation of the unburned gas caused by the closureof the air outlet 90.

The controller 200 may stop the gas supply to stop the operation of thecooking apparatus 1 and rotate the first convection fan 51 b and thesecond convection fan 52 b for the predetermined time to discharge theunburned gas. After the predetermined time elapses since the dischargeof the unburned gas, the controller 200 may resume the gas supply tostart the operation of the cooking apparatus 1.

That is, in response to the completion of the air circulation in thecavity 40 and the completion of the discharge of unburned gas while thedoor 2 a of the cooking apparatus 1 is locked, the controller 200 maystart the pre-heating, again. After the predetermined time elapses sincethe start of the pre-heating, the controller 200 may determine whetherthe temperature of the cavity 40 is greater than or equal to the secondreference temperature. In response to the temperature of the cavity 40being greater than or equal to the second reference temperature, thecontroller 200 may determine that the difficulty does not occur in thecombustion process of the appliance 1, and control the cooking apparatus1 to start the cooking.

On the other hand, in response to the temperature of the cavity 40 beingless than the second reference temperature even after the pre-heatingagain for the predetermined time, the controller 200 may determine thatthe difficulty occurs in the combustion process of the cooking apparatus1, such as the generation of the unburned gas caused by the closure ofthe air outlet 90, and the controller 200 may stop the operation of thecooking apparatus 1, again. In addition, the controller 200 may stop theoperation of the burner 60 to stop the gas supply, rotate the convectionfan 50 b for the predetermined time to circulate the air inside thecavity 40, and maintain the door 2 a in a locked state.

As described above, the controller 200 may repeat to detect thetemperature of the cavity 40 of the cooking apparatus 1 so as todetermine the abnormal combustion of the cooking apparatus 1, andaccordingly, to stop the operation of the cooking apparatus 1 and toresume the operation at the expiration of the predetermined time. Inresponse to the repeat occurrence of the difficulty in the combustionprocess of the cooking apparatus 1 by a predetermined number of times,the controller 200 may stop the operation of the cooking apparatus 1 andcontrol the operation not to start again.

After the cooking apparatus 1 completes the pre-heating of the cavity 40and starts the cooking mode (1060), the temperature sensor 80 may detectthe temperature of the cavity 40 (1065).

The controller 200 may determine whether the temperature of the cavity40 detected by the temperature sensor 80 is greater than or equal to athird reference temperature during the cooking of the cooking apparatus1 (1070). The third reference temperature may be a reference temperaturerequired for cooking the food accommodated in the cavity 40, andcorrespond to a set temperature input by the user in advance through theinput button 5 a and temperature data stored in advance in the memory220.

That is, the controller 200 may determine whether the cooking apparatus1 is heated to the predetermined temperature or more to cook food for acertain period of time since the start of the cooking. In general, asshown in FIG. 7, the temperature of the cavity 40 for cooking rises tothe third reference temperature or more.

In response to the temperature of the cavity 40 being greater than orequal to the third reference temperature during the cooking, thecontroller 200 may determine that the difficulty does not occur in thecombustion process of the cooking apparatus 1, and may control thecooking apparatus 1 to continue the cooking (1090).

However, as described above in FIG. 4, due to the closure of the airoutlet 90 such as the state in which a user places an object ob on theair outlet 90, the waste gas burned inside the cooking apparatus 1 maystay inside the cavity 40 without being discharged to the outsidethrough the air outlet 90. Therefore, air for combustion may not besupplied to the inside of the cooking apparatus 1, which causes thegeneration of the unburned gas.

That is, gas is not completely burned inside the cooking apparatus 1,and thus the temperature of the cavity 40 does not rise. Accordingly, asillustrated in FIG. 9, a temperature of the cavity 40 detected by thetemperature sensor 80 is less than the third reference temperature.

In response to the temperature of the cavity 40 being less than thethird reference temperature, the controller 200 may determine whetherthe second reference time t2 elapses since the start of cooking of thecooking apparatus 1 (1080).

In response to the second reference time t2 not elapsing, thetemperature sensor 80 may detect the temperature of the cavity 40 again(1065), and the controller 200 may compare the temperature of the cavity40 detected by the temperature sensor 80 with the third referencetemperature, again (1070).

The controller 200 may determine whether the temperature of the cavity40 is less than the third reference temperature during the secondreference time t2 after the start of the cooking.

In response to the temperature of the cavity 40 being greater than orequal to the third reference temperature at least once during the secondreference time t2 after the start of the cooking, the controller 200 maydetermine that the difficulty does not occur in the combustion processof the cooking apparatus 1.

In response to the temperature of the cavity 40 continuously being lessthan the third reference temperature during the second reference time t2after the start of the cooking, the controller 200 may determine thatthe difficulty occurs in the combustion process of the cooking apparatus1, such as the generation of the unburned gas caused by the closure ofthe air outlet 90, and the controller 200 may stop the operation of thecooking apparatus 1.

Particularly, the controller 200 may control the operation of the burner60 to be stopped (1081). That is, by controlling the first burner valve61 a and the second burner valve 62 a included in the first burner 61and the second burner 62, respectively, the controller 200 may stop thegas supply so as to prevent unburned gas from being filled in thecooking apparatus 1.

Further, the controller 200 may control the convection fan 50 b torotate for a predetermined second circulation time (1082). That is, bycontrolling each of the first convection fan Mb and the secondconvection fan 52 b to rotate for the predetermined time, the controller200 may circulate the air inside the cavity 40 and allow unburned gasinside the cavity 40 to be discharged to the outside of the cookingapparatus 1. The second circulation time in which the convention fan 50b rotates may be the same as or different from the first circulationtime, or may vary according to an elapsed time of the cooking progress.

Further, the controller 200 may control the door 2 a of the cookingapparatus 1 to be locked for a predetermined second locking time (1083).That is, the controller 200 may control the door 2 a of the cookingapparatus 1 to be locked for the predetermined time until the unburnedgas of the cooking apparatus 1 is discharged to the outside ordisappears, and thus the controller 200 may secure the user's safety.The second locking time in which the door 2 a is locked may be the sameas or different from the first locking time or may vary according to anelapsed time of the cooking progress.

In addition, the controller 200 may control the notification device 400to transmit the warning sound indicating that the difficulty occurs inthe combustion process of the cooking apparatus 1, such as thegeneration of the unburned gas due to the closure of the air outlet 90(1084).

The notification device 400 may be implemented in the form of a speakerthat outputs a voice signal or a sound signal, and may output a warningmessage regarding abnormal operation of the cooking apparatus 1 as apredetermined sound signal such as a voice or a warning sound. Thenotification device 400 may output the warning message once or mayoutput the warning message several times according to a predeterminedsetting.

Similarly, the controller 200 may control the display 5 b to display thewarning message indicating that the difficulty occurs in the combustionprocess of the cooking apparatus 1, such as the generation of theunburned gas due to the closure of the air outlet 90 (1084).

That is, as shown in FIG. 10, the controller 200 may display the messageregarding the abnormal operation of the cooking apparatus 1 on thedisplay 5 b, and a user may identify that the operation of the cookingapparatus 1 is stopped due to the generation of the unburned gas causedby the closure of the air outlet 90 during the cooking process of thecooking apparatus 1.

In addition, the controller 200 may control the communication circuitry300 to transmit at least one data of the warning sound or the warningmessage indicating that the difficulty occurs in the combustion processof the cooking apparatus 1, such as the generation of the unburned gasdue to the closure of the air outlet 90, to the user terminal 600(1085).

Based on the data received from the cooking apparatus 1 through thecommunication circuitry 300, the user terminal 600 may output apredetermined sound signal, such as a voice or a warning sound,regarding the occurrence of the difficulty in the combustion process ofthe cooking apparatus 1, such as the generation of the unburned gas dueto the closure of the air outlet 90.

Further, as shown in FIG. 11, the user terminal 600 may display thewarning message indicating that the difficulty occurs in the combustionprocess of the cooking apparatus 1.

The controller 200 may stop the gas supply to stop the operation of thecooking apparatus 1 and rotate the first convection fan 51 b and thesecond convection fan 52 b for the predetermined time to discharge theunburned gas. After the predetermined time elapses since the dischargeof the unburned gas, the controller 200 may resume the gas supply tostart the operation of the cooking apparatus 1.

That is, in response to the completion of the air circulation in thecavity 40 and the completion of the discharge of unburned gas while thedoor 2 a of the cooking apparatus 1 is locked, the controller 200 mayresume the cooking operation of the cooking apparatus 1. In response tothe expiration of the predetermined time after the restarting of thepre-heating, the controller 200 may determine whether the temperature ofthe cavity 40 is greater than or equal to the third referencetemperature. In response to the temperature of the cavity 40 beinggreater than or equal to the third reference temperature, the controller200 may determine that the difficulty does not occur in the combustionprocess of the appliance 1, and control the cooking apparatus 1 toproceed with the cooking.

On the other hand, in response to the temperature of the cavity 40 beingless than the third reference temperature even after the pre-heatingagain for the predetermined time, the controller 200 may determine thatthe difficulty occurs in the combustion process of the cooking apparatus1, such as the generation of the unburned gas caused by the closure ofthe air outlet 90, and the controller 200 may stop the operation of thecooking apparatus 1, again. In addition, the controller 200 may stop theoperation of the burner 60 to stop the gas supply, rotate the convectionfan 50 b for the predetermined time to circulate the air inside thecavity 40, and maintain the door 2 a in the locked state.

As described above, the controller 200 may repeat to detect thetemperature of the cavity 40 of the cooking apparatus 1 so as todetermine the abnormal combustion of the cooking apparatus 1, andaccordingly, to stop the operation of the cooking apparatus 1 and toresume the operation at the expiration of the predetermined time. Inresponse to the repeat occurrence of the difficulty in the combustionprocess of the cooking apparatus 1 by a predetermined number of times,the controller 200 may stop the operation of the cooking apparatus 1 andcontrol the operation not to start again. The user listens to thewarning sound output from the user terminal 600, or checks the warningmessage displayed on the user terminal 600, thereby identifying that theoperation of the cooking apparatus 1 is stopped due to the generation ofthe unburned gas caused by the closure of the air outlet 90.

As described above, according to the cooking apparatus and the controlmethod thereof according to one embodiment of the disclosed disclosure,it is possible to obtain an effect of improving stability of a productoperation by stopping the operation of the cooking apparatus 1 byidentifying the situation, in which the air outlet 90 is closed, bydetecting the internal temperature of the cavity 40 of the cookingapparatus 1. In addition, it is possible to obtain an effect of securingthe safety of the user from the difficulty that the flame is dischargedout of the oven due to sudden gas combustion caused by opening of thecavity 40 filled with the unburned gas.

FIG. 12 is a flowchart illustrating a control flow in cooking of thecooking apparatus according to one embodiment of the present disclosure.FIG. 13 is a graph illustrating a temperature of the cavity of thecooking apparatus according to one embodiment of the present disclosure.FIG. 14 is a graph illustrating a temperature variation of the cavity ofthe cooking apparatus according to one embodiment of the presentdisclosure.

Referring to FIGS. 12 to 14, in response to the start of the operationof the cooking apparatus 1, the temperature sensor 80 may detect thetemperature of the cavity 40 (1100). In response to the temperature ofthe cavity 40 being greater than or equal to the first referencetemperature, the controller 200 may control the cooking apparatus 1 tostart heating for the cooking (1160), and in response to the temperatureof the cavity 40 being less than the first reference temperature, thecontroller 200 may control the cooking apparatus 1 to start heating forthe pre-heating (1120).

Operations 1100, 1110, and 1120 may be the same as the operations 1000,1010, and 1020 illustrated in FIG. 5, and thus descriptions ofoperations 1100, 1110, and 1120 are replaced by the description of theoperations 1000, 1010, and 1020.

The temperature sensor 80 may detect the temperature of the cavity 40(1130).

The controller 200 may determine whether a temperature variation of thecavity 40 is greater than or equal to a first reference value (1140). Inthis case, the first reference value may be a set temperature input by auser through the input button 5 a in advance or may be temperature datastored in the memory 220 in advance.

The controller 200 may store the temperature of the cavity 40 detectedby the temperature sensor 80 in a time-series manner in the memory 220,and the controller 200 may obtain the temperature variation of thecavity 40 based on the temperature of the cavity 40 stored intime-series in the memory 220.

The controller 200 may obtain a temperature variation at differenttimes. For example, as shown in FIG. 13, the controller 200 may obtain atemperature T1 from the temperature sensor 80 at a time t1, obtain atemperature T2 at a time t2, a temperature T3 at a time t3, and atemperature T4 at a time t4. The controller 200 may obtain a temperaturevariation between successive times. The controller 200 may obtain atemperature variation T2-T1 between time t1 and time t2. Further, thecontroller 200 may obtain a temperature variation T4-T3 between time t3and time t4.

The controller 200 may compare the temperature variation of the cavity40 with the first reference value, and determine whether the temperaturevariation of the cavity 40 is greater than the first reference value.

During the normal operation, the temperature of the cavity 40 mayincrease relatively constantly as shown in FIG. 13, and the temperaturevariation of the cavity 40 may be a constant value as shown in FIG. 14.

On the other hand, in response to the gas being incompletely combustedor not combusted due to the closure of the air outlet, the temperatureof the cavity 40 may rapidly increase in an initial stage of combustion.Due to the closure of the air outlet, heat may not be discharged to theoutside, and the temperature of the cavity 40 may rapidly rise until areference time tR in which all the oxygen in the cavity 40 is burned.After the reference time tR in which all of the oxygen in the cavity 40is burned, the gas may be incompletely combusted or not combusted, andthe temperature of the cavity 40 may gradually increase.

As mentioned above, in response to the determination that thetemperature variation of the cavity 40 is decreased after the referencetime tR, the controller 200 may determine that the gas is incompletelycombusted or not combusted due to the closure of the air outlet.

In order to determine whether the cooking apparatus 1 operates normally,the controller 200 may determine whether the temperature variation ofthe cavity 40 is greater than the first reference value. The firstreference value may be set to a value less than a temperature variationof the cavity 40 during the normal operation.

In response to the temperature variation of the cavity 40 being greaterthan or equal to the first reference value (yes in 1140), the controller200 determines whether a third reference time elapses since the start ofthe heating (1150).

The controller 200 may determine whether the temperature variation ofthe cavity 40 is greater than or equal to the first reference valueduring the third reference time since the start of the heating.

In response to the determination that the third reference time does notelapse since the start of the heating (no in 1150), the temperaturesensor 80 may detect the temperature of the cavity 40 and the controller200 may repeat to determine whether the temperature variation of thecavity 40 is greater than or equal to the first reference value.

In response to the determination that the third reference time elapsessince the start of the heating (yes in 1150), the controller 200continues to heat the cavity 40 (1160).

In response to the temperature variation of the cavity 40 being greaterthan or equal to the first reference value during the third referencetime, the controller 200 may determine that the difficulty does notoccur in the combustion process of the cooking apparatus 1. Therefore,the controller 200 may control the cooking apparatus 1 to proceed withthe cooking.

In response to the temperature variation of the cavity 40 being lessthan the first reference value (no in 1140), the controller 200determines whether a period of time, in which the temperature variationof the cavity 40 is less than the first reference value, is greater thanor equal to a fourth reference time (1170).

Particularly, the controller 200 may determine whether the temperaturevariation of the cavity 40 is less than the first reference time duringthe fourth reference time or more.

In response to the determination that the period of time, in which thetemperature variation of the cavity 40 is less than the first referencevalue, is less than the fourth reference time (no in 1170), thetemperature sensor 80 detects the temperature of the cavity 40 and thecontroller 200 repeats to determine whether the temperature variation ofthe cavity 40 is greater than or equal to or the first reference value.

The temperature variation of the cavity 40 may change for a variety ofreasons. Therefore, in response to the temperature variation of thecavity 40 being less than the first reference value for a short time,the controller 200 may re-determine whether the temperature variation ofthe cavity 40 is greater than or equal to the first reference value inorder to confirm that the gas is incompletely combusted or notcombusted.

In response to the determination that the period of time, in which thetemperature variation of the cavity 40 is less than the first referencevalue, is greater than or equal to the fourth reference time (yes in1170), the controller 1180 stops the heating (1180).

In response to the temperature variation of the cavity 40 being lessthan the first reference value for the fourth reference time or longer,the controller 200 may determine that the gas is incompletely combustedor not combusted.

For example, as shown in FIGS. 13 and 14, the temperature of the cavity40 constantly rises during the normal operation, and the temperaturevariation of the cavity 40 may fluctuate within a certain range.

On the other hand, in response to the gas being incompletely combustedor not combusted, the temperature variation of the cavity 40 decreasesafter the reference time tR in which all the oxygen in the cavity 40 isburned, and the temperature variation of the cavity 40 is maintained ata value less than the first reference value.

Accordingly, in response to the temperature variation of the cavity 40being maintained at the value less than the first reference value forthe fourth reference time, the controller 200 may identify that the gasis incompletely combusted or not combusted.

For this reason, the controller 200 may stop the cooking. While thecooking is in progress, the controller 200 may control the operation ofthe burner 60 to be stopped, control the convection fan 50 b to rotatefor the predetermined second circulation time and control the door 2 ato be maintained in the locked state for the predetermined secondlocking time. While the cooking is in progress, the controller 200 maycontrol the notification device 400 to output the warning soundindicating that the difficulty occurs in the combustion process of thecooking apparatus 1, such as the generation of the unburned gas due tothe closure of the air outlet 90. The controller 200 may control thedisplay 5 b to display the warning message indicating that thedifficulty occurs in the combustion process of the cooking apparatus 1,such as the generation of the unburned gas due to the closure of the airoutlet 90. In addition, the controller 200 may control the communicationcircuitry 300 to transmit at least one data of the warning sound or thewarning message indicating that the difficulty occurs in the combustionprocess of the cooking apparatus 1, such as the generation of theunburned gas due to the closure of the air outlet 90, to the userterminal 600.

As described above, according to the cooking apparatus and the controlmethod thereof according to one embodiment of the disclosed disclosure,it is possible to obtain an effect of improving stability of a productoperation by stopping the operation of the cooking apparatus 1 byidentifying the situation, in which the air outlet 90 is closed, bydetecting the difference in the temperature of the cavity 40 of thecooking apparatus 1. In addition, it is possible to obtain an effect ofsecuring the safety of the user from the difficulty that the flame isdischarged out of the oven due to sudden gas combustion caused byopening of the cavity 40 filled with the unburned gas.

As mentioned above, the cooking apparatus 1 may determine that the gasis incompletely combusted or not combusted based on the temperaturevariation of the cavity 40. Accordingly, the cooking apparatus 1 maydistinguish a situation, in which the temperature of the cavity 40 isnot increased due to combustion failure, from a situation, in which thetemperature of the cavity 40 is not increased due to another heatingfailure.

FIG. 15 is a flowchart illustrating a control flow in the cooking of thecooking apparatus according to one embodiment of the present disclosure.FIG. 16 is a graph illustrating a change in temperature variation of thecavity of the cooking apparatus according to one embodiment of thepresent disclosure.

Referring to FIGS. 15 and 16, in response to the start of the operationof the cooking apparatus 1, the temperature sensor 80 may detect thetemperature of the cavity 40 (1200). The controller 200 may compare thetemperature of the cavity 40 detected by the temperature sensor 80 withthe first reference temperature (1210). In response to the temperatureof the cavity 40 being greater than or equal to the first referencetemperature, the controller 200 may control the cooking apparatus 1 tostart heating for the cooking (1160), and in response to the temperatureof the cavity 40 being less than the first reference temperature, thecontroller 200 may control the cooking apparatus 1 to start heating forthe pre-heating (1220).

Operations 1200, 1210, and 1220 may be the same as the operations 1000,1010, and 1020 illustrated in FIG. 5, and thus descriptions ofoperations 1200, 1210, and 1220 are replaced by the description of theoperations 1000, 1010, and 1020.

The temperature sensor 80 may detect the temperature of the cavity 40(1230).

The controller 200 may determine whether the change in the temperaturevariation of the cavity 40 is greater than or equal to the secondreference value (1240). In this case, the second reference value may bea set temperature input by the user through the input button 5 a inadvance or may be temperature data stored in the memory 220 in advance.

The controller 200 may store the temperature of the cavity 40 detectedby the temperature sensor 80 in a time-series manner in the memory 220,and the controller 200 may obtain the change in the temperaturevariation of the cavity 40 based on the temperature of the cavity 40stored in time-series in the memory 220.

The controller 200 may obtain a temperature variation at differenttimes. For example, the controller 200 may obtain a temperaturevariation between successive times. The controller 200 may obtain atemperature variation T2-T1 between time t1 and time t2. Further, thecontroller 200 may obtain a temperature variation T4-T3 between time t3and time t4.

The controller 200 may obtain a change in the temperature variation atdifferent times. For example, the controller 200 may obtain a change inthe temperature variation (T4-T3)-(T2-T1) at the time t4 based on thechange between the temperature variation T2-T1 at the time t2 and thetemperature variation T4-T3 at the time t4.

The controller 200 may compare the change in the temperature variationof the cavity 40 with the second reference value, and determine whetherthe change in the temperature variation of the cavity 40 is greater thanthe second reference value.

During the normal operation, the temperature of the cavity 40 mayincrease relatively constantly, and the temperature change of the cavity40 may be approximately “0” (zero) as shown in FIG. 16.

On the other hand, in response to the gas being incompletely combustedor not combusted due to the closure of the air outlet, the temperatureof the cavity 40 may rapidly increase before the reference time tR andgradually increase after the reference time tR. At the reference timetR, an inflection point, in which the temperature variation of thecavity 40 is decreased, that is, the change in the temperature variationof the cavity 40 becomes less than “0”, may occur.

As mentioned above, in response to the determination that the change inthe temperature variation of the cavity 40 is decreased (moreparticularly, it is less than “0” (zero)) after the reference time tR,the controller 200 may determine that the gas is incompletely combustedor not combusted due to the closure of the air outlet.

In order to determine whether the cooking apparatus 1 operates normally,the controller 200 may determine whether the change in the temperaturevariation of the cavity 40 is greater than the second reference value.The second reference value may be set to a value less than “0” (zero).

In response to the change in the temperature variation of the cavity 40being greater than or equal to the second reference value (yes in 1240),the controller 200 determines whether a third reference time elapsessince the start of the heating (1250).

In response to the determination that the third reference time does notelapse since the start of the heating (no in 1250), the temperaturesensor 80 detects the temperature of the cavity 40 and the controller200 repeats to determine whether the change in the temperature variationof the cavity 40 is greater than or equal to the second reference value.

In response to the determination that the third reference time elapsessince the start of the heating (yes in 1250), the controller 200continues to heat the cavity 40 (1260).

In response to the change in the temperature variation of the cavity 40being greater than or equal to the second reference value for the thirdreference time since the start of the heating, the controller 200 maydetermine that the cooking apparatus 1 performs a normal combustionoperation.

In response to the change in the temperature variation of the cavity 40being less than the second reference value (no in 1240), the controller200 determines whether a period of time, in which the change in thetemperature variation of the cavity 40 is less than the second referencevalue, is greater than or equal to a fifth reference time (1270).

Particularly, the controller 200 may determine whether the change in thetemperature variation of the cavity 40 is less than the second referencevalue during the fifth reference time.

In response to the determination that the period of time, in which thechange in the temperature variation of the cavity 40 is less than thesecond reference value, is less than the fifth reference time (no in1270), the temperature sensor 80 detects the temperature of the cavity40 and the controller 200 repeats to determine whether the change in thetemperature variation of the cavity 40 is greater than or equal to thesecond reference value.

In response to the determination that the period of time, in which thechange in the temperature variation of the cavity 40 is less than thesecond reference value, is greater than or equal to the fourth referencetime (yes in 1270), the controller 1180 stops the heating (1280).

In response to the change in the temperature variation of the cavity 40being less than the second reference value for the fourth reference timeor more, the controller 200 may determine that the gas is incompletelycombusted or not combusted.

For example, as shown in FIG. 16, the change in the temperaturevariation of the cavity 40 during the normal operation may fluctuatearound approximately “0” (zero).

On the other hand, in response to the gas being incompletely combustedor not combusted, the temperature variation of the cavity 40 isdecreased at the reference time tR, in which all the oxygen in thecavity 40 is burned, and the change in the temperature variation of thecavity 40 is less than “0” (zero).

Accordingly, in response to the period of time, in which the change inthe temperature variation of the cavity 40 is less than the secondreference value, being maintained for the fourth reference time, thecontroller 200 may identify that the gas is incompletely combusted ornot combusted.

For this reason, the controller 200 may stop the cooking.

As described above, the cooking apparatus 1 may determine that the gasis incompletely combusted or not combusted based on the change in thetemperature variation of the cavity 40. Accordingly, the cookingapparatus 1 may distinguish between the situation in which thetemperature of the cavity 40 is not rapidly increased due to arelatively low external temperature and the situation in which thetemperature of the cavity 40 is not increased due to poor combustion.

Meanwhile, the disclosed embodiments may be embodied in the form of arecording medium storing instructions executable by a computer. Theinstructions may be stored in the form of program code and, whenexecuted by a processor, may generate a program module to perform theoperations of the disclosed embodiments. The recording medium may beembodied as a computer-readable recording medium.

The computer-readable recording medium includes all kinds of recordingmedia in which instructions which can be decoded by a computer arestored. For example, there may be a Read Only Memory (ROM), a RandomAccess Memory (RAM), a magnetic tape, a magnetic disk, a flash memory,and an optical data storage device.

Storage medium readable by machine, may be provided in the form of anon-transitory storage medium. “Non-transitory” means that the storagemedium is a tangible device and does not contain a signal (e.g.,electromagnetic wave), and this term includes a case in which data issemi-permanently stored in a storage medium and a case in which data istemporarily stored in a storage medium.

The method according to the various disclosed embodiments may beprovided by being included in a computer program product. Computerprogram products may be traded between sellers and buyers ascommodities. Computer program products are distributed in the form of adevice-readable storage medium (e.g., compact disc read only memory(CD-ROM)), or are distributed directly or online (e.g., downloaded oruploaded) between two user devices (e.g., smartphones) through anapplication store (e.g., Play Store™). In the case of onlinedistribution, at least a portion of the computer program product (e.g.,downloadable app) may be temporarily stored or created temporarily in adevice-readable storage medium such as the manufacturer's server, theapplication store's server, or the relay server's memory.

While the present disclosure has been particularly described withreference to exemplary embodiments, it should be understood by those ofskilled in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present disclosure.

What is claimed is:
 1. A cooking apparatus comprising: a body forming acavity; a temperature sensor configured to detect a temperature of thecavity; a burner configured to heat the cavity by burning gaseous fuel;and a controller configured to identify a temperature variation of thecavity based on the temperature detected by the temperature sensor, andconfigured to stop an operation of the burner based on a change in thetemperature variation of the cavity being less than a reference value.2. The cooking apparatus of claim 1, wherein the controller isconfigured to identify the change in the temperature variation of thecavity based on a change between a temperature variation of the cavityat a first time and a temperature variation of the cavity at a secondtime.
 3. The cooking apparatus of claim 1, wherein the controller isconfigured to stop the operation of the burner based on the change inthe temperature variation of the cavity being less than the referencevalue during a first reference time.
 4. The cooking apparatus of claim1, wherein the controller is configured to continue the operation of theburner based on the change in the temperature variation of the cavitybeing greater than or equal to the reference value during a secondreference time.
 5. The cooking apparatus of claim 1, wherein anoperation of the cooking apparatus comprises a pre-heating operation ofthe cavity and a cooking operation of food accommodated in the cavity,wherein the controller is configured to: control the cooking apparatusto start the cooking operation in response to the temperature of thecavity detected by the temperature sensor before the pre-heatingoperation being greater than or equal to a reference temperature, andcontrol the cooking apparatus to start the pre-heating operation inresponse to the temperature of the cavity being less than the referencetemperature.
 6. The cooking apparatus of claim 1, further comprising: aconvection fan, wherein the controller is configured to drive theconvection fan to circulate air inside the cavity based on the change inthe temperature variation of the cavity being less than the referencevalue.
 7. The cooking apparatus of claim 1, further comprising: adisplay, wherein the controller is configured to cause the display todisplay a message indicating an operation error of the cooking apparatusbased on the change in the temperature variation of the cavity beingless than the reference value.
 8. A control method of a cookingapparatus including a body, the control method comprising: driving aburner configured to heat a cavity of the cooking apparatus by burninggaseous fuel; detecting a temperature of the cavity; identifying atemperature variation of the cavity based on the detected temperature;and stopping an operation of the burner based on a change in thetemperature variation of the cavity being less than a reference value.9. The control method of claim 8, wherein the identifying of the changein the temperature variation of the cavity comprises identifying thechange in the temperature variation of the cavity based on a changebetween a temperature variation of the cavity at a first time and atemperature variation of the cavity at a second time.
 10. The controlmethod of claim 8, wherein the stopping of the operation of the burnercomprises stopping the operation of the burner based on the change inthe temperature variation of the cavity being less than the referencevalue during a first reference time.
 11. The control method of claim 8,further comprising: continuing the operation of the burner based on thechange in the temperature variation of the cavity being greater than orequal to the reference value during a second reference time.
 12. Thecontrol method of claim 8, wherein an operation of the cooking apparatuscomprises a pre-heating operation for pre-heating the cavity and acooking operation for cooking food accommodated in the cavity, whereinthe control method further comprises starting the cooking operation inresponse to the temperature of the cavity detected by the temperaturesensor before the pre-heating operation, being greater than or equal toa first reference temperature, and starting the pre-heating operation inresponse to the temperature of the cavity being less than the referencetemperature.
 13. The control method of claim 8, further comprising:driving a convection fan to circulate air inside the cavity based on thechange in the temperature variation of the cavity being less than thereference value.
 14. The control method of claim 8, further comprising:controlling a display to display a message indicating an operation errorof the cooking apparatus based on the change in the temperaturevariation of the cavity being less than the reference value.
 15. Acooking apparatus comprising: a body forming a cavity; a temperaturesensor configured to detect a temperature of the cavity; a burnerconfigured to heat the cavity by burning gaseous fuel; and a controllerconfigured to stop an operation of the burner in response to thetemperature of the cavity detected by the temperature sensor after apredetermined time elapses since an operation of the cooking apparatusstarts, being less than a predetermined temperature.
 16. The cookingapparatus of claim 15, wherein the operation of the cooking apparatuscomprises pre-heating for pre-heating the cavity and cooking for cookingfood accommodated in the cavity, wherein the controller is configured tocontrol the cooking apparatus to start the cooking in response to thetemperature of the cavity detected by the temperature sensor before thepre-heating, being greater than or equal to a predetermined firstreference temperature, and configured to control the cooking apparatusto start the pre-heating in response to the temperature of the cavitybeing less than the predetermined first reference temperature.
 17. Thecooking apparatus of claim 16, wherein the controller is configured tostop the operation of the burner in response to the temperature of thecavity detected by the temperature sensor after a predetermined firstreference time elapses since the pre-heating of the cooking apparatusstarts, being less than a predetermined second reference temperature.18. The cooking apparatus of claim 16, wherein the controller isconfigured to control the cooking apparatus to continue the cooking inresponse to the temperature of the cavity detected by the temperaturesensor after the predetermined second reference time elapses since thecooking of the cooking apparatus starts, being greater than or equal toa predetermined third reference temperature.
 19. The cooking apparatusof claim 17, wherein the controller is configured to stop the operationof the burner in response to the temperature of the cavity detected bythe temperature sensor after the predetermined second reference timeelapses since the cooking of the cooking apparatus starts, being lessthan the predetermined third reference temperature.
 20. The cookingapparatus of claim 17, further comprising: a convection fan, wherein thecontroller is configured to drive the convection fan to circulate airinside the cavity in response to the temperature of the cavity detectedby the temperature sensor after the predetermined time elapses since theoperation of the cooking apparatus starts, being less than thepredetermined temperature.